CCI 200 primers causing slower velocity?

[LittleLebowski]

I’m seeing consistently slow velocities with all handloads out of my 20” 700 as recorded by my MagnetoSpeed Sporter, as in 2625fps for Hornady 178gr ELDM over 45.0gr of Varget. Might this be my CCI 200 primers? I’m guessing I should switch to magnum primers.

[mtnbkr]

Slow compared to what exactly? The same load but with different primers? Compared with the loading manual? Varget is a fastish rifle powder and shouldn't need a mag primer.

308win?

The 175gr HPBT load on Hodgdon's reloading site uses a non-mag match primer with a compressed 45gr charge of Varget.

Chris

[LittleLebowski]

Yeah, 308. I can’t break 2500fps with 195s and JV can with the same powder and bullet weight.

[mtnbkr]

Yeah, 308. I can’t break 2500fps with 195s and JV can with the same powder and bullet weight.

Same charge as well? What about the gun?

Guns are weird. I've had guns that run slow (GP100 and Winchester 70 FWT 6.5x55) and others that run fast (Ruger Redhawk and Savage Hog Hunter 308). If you're confident your load is not overpressure (and vice versa for his), try them in each other's guns and see if the same trend holds.

It won't hurt to try another primer, but I would be surprised if it made a big difference.

Chris

[LittleLebowski]

Same charge as well? What about the gun?

Guns are weird. I've had guns that run slow (GP100 and Winchester 70 FWT 6.5x55) and others that run fast (Ruger Redhawk and Savage Hog Hunter 308). If you're confident your load is not overpressure (and vice versa for his), try them in each other's guns and see if the same trend holds.

It won't hurt to try another primer, but I would be surprised if it made a big difference.

Chris

Same rifle, same charge. I should be hitting 2600ish with the 178s and 45.0gr of Varget.

[mtnbkr]

Same rifle, same charge. I should be hitting 2600ish with the 178s and 45.0gr of Varget.

But different primer or same? Any idea on round count for the two rifles? Wear changes how a gun reacts to a load.

Chris

[JohnO]

Same rifle, same charge. I should be hitting 2600ish with the 178s and 45.0gr of Varget.

Meaning? Same make and model?

No two rifles are going to have identically cut chambers, leads and bores. All that will factor into how a particular load performs.

[mtnbkr]

LL, if you're not married to Varget, give RL17 a try. I'm getting 2800fps with a 180gr SPBT in my 20" 308win. That's a book load. Apparently RL17 has a flatter pressure curve, so it "pushes" longer, giving you more velocity at a given pressure. It might solve your velocity problem.

Chris

[LittleLebowski]

Meaning? Same make and model?

No two rifles are going to have identically cut chambers, leads and bores. All that will factor into how a particular load performs.

Same rifle. One rifle.

[mtnbkr]

Same rifle. One rifle.

oh! Well, that's different.

ok, same gun, same powder charge.

Safe to assume same brass and same bullet? What about brass prep and seating depth?

Since you asked about the primer, are you using different primers?

Chris